This invention relates to a slotted set screw and, particularly, to one provided with a cut metal waste storing recess respectively provided at two opposite ends of the slot of a set crew and with the two waste storing recesses being parallel to each other and having a large opening so that cut metal waste produced by cutting threads in an outer surface of the shank of the set screw may naturally fall into the two waste storing recesses without falling into and clogging the slot of the set screw during processing of the set screw.